Belt for fourdrinier machines



Sept. 19, 1933. H. UNDSAY ET AL 1,927,498

BELT FOR FOURDRINIER MACHINES Filed Nov. 28, 1931 Patented Sept. i9, QSE

BELT FOR FRDRHNEIER MIACHINIES Hamilton Lindsay, Shaker Heights, (Dhio, and Edward ll. Buell, Niagara Falls, N. Y., assignors to The Lindsay Wire Weaving Company, Cleveland, Ohio, a corporation of h50 application November 28, 193i Serial No. 577,838

6 Claims.

This invention relates to woven wire fabric that is used in the manufacture of belts for Fourdrinier machines. The increased width of paper machines and the increased speed at which Fourdrinier belts are operated has necessitated greater tensile strength in the belts. Such development has been gradual and as a result, the meshes of Fourdrinier wires have become more and more rectangular with a greater difference between the warp and weft count per inch, as heavier sizes of wires are incorporated into the web.

This development has continued over a long period of years until at the present time sixty mesh fabric is now commonly made of sixty warp wires to the inch and forty weft wires to the inch. Furthermore, the warp wires have a diameter of .009 of an inch; while the weft Wires have a diameter of .01o of an inch. This resulted in a mesh opening of .015 of an inch long and .008 of an inch wide. Another arrangement, which gives equivalent drainage with greater strength and durability, utilizes fifty-five warp wires to the inch and thirty-six weft Wires to the inch, using a warp wire of .010 of an inch in diameter and a weft Wire of .011 of an inch in diameter, and providling a mesh opening of .017 of an inch by .008 of an inch. A further 'consideration in papermaking belts is that the pulp is supported by the tops of the warp knuckles without adequate support from the weft wires, except for forming deep depressions in the web of paper. These depressions do not exist on the top side of the sheet so that there is a pronounced difference between the two sides of the sheet. Eiorts have been made to eliminate this objectionable feature by rolling the belt orgrinding off the knuckles of the fabric, but these processes cannot be accomplished without seriously interfering with the flexibility and durability of the belt.

We propose to eliminate the objections inherent in the projecting Warp knuckles by raising a crimp on the weft knuckles, so as to bring the tops of the weft knuckles substantially in a plane with the tops of the warp knuckles, and we propose to accomplish this during the weaving operation by the proper selection of weaves and! wire sizes. This effectively reduces the depth of the wire marks and enables the smaller depressions to be more easily smoothed out on the presses of the paper machine. This method is Well adapted for the use of a twill weave wherein the short knuckles are disposed on the top of the cloth and the long knuckles are disposed on the bottom of the cloth. Furthermore, this method enables us to reverse the tendency toward more rectangular meshes, and to make the mesh opening more nearly square, and still use the multiple or twill Weave.

The high rate of speed at which Fourdrinier machines are operated at the present time also 6@ increases the dificulty of the belt to hold the pulp, for the belt has a tendency to creep with reference to thepulp` It is 'an object of our invention therefore to so weave the fabric that the Warp wires are spaced farther apart, thus allowing more room for the weft knuckles and permitting the weft knuckles to be raised above their previous position. This in effect provides a series of steps which extend across, the belt and thereby I serve to keep the pulp more securely in contact with the belt while the sheet is being formed. We have found that this operation can be Aiatisfactorily accomplished if the tops of the weft knuckles lie substantially in the plane of the tops of the warp knuckles.

Referring now to the drawing, Fig. l is a top plan view on an enlarged scale, of a part of a belt that is made in accordance with our invention, and Fig. 2 is a section taken on a further enlarged scale on the line 2-2 in Fig. 1. s@

In the drawing, we have illustrated a twill Weave wherein the warp wires are indicated at 10, and the weft wires are indicated at 1l. The spacing and selection of wire sizes is such that the tops of the weft knuckles lie substantially in the same plane as the tops of the Warp knuckles. This is shown particularly inFig. 2 wherein the common plane of the warp and weft knuckles is indicated by the broken line 12.

We have found that satisfactory results can be obtained if a fabric embodying our invention is made by using a warp Wire of ;0l0 of an inch in diameter and a weft wire of .009 o an inch in diameter, with 55 warp wires and Soweit wires to the inch. cThis arrangement is satisfactory in'tWill weaves to replace a sixty by forty mesh fabric having a plain weave.

Apart from the advantages of greater durability and less wire marks, which are obtained No with this arrangement, we have found that the twill weave can now be used for the manufacture of fine grades of paper, whereas heretofore they have been limited to the manufacture of relative ly coarse paper. This result follows by reason ci' the fact that the weaving provides a relatively square mesh, which will not lose so much iine stock during the formation of the web. Furthermore, a twill weave provides a longer life for a belt' when used in the manufacture of ne Hg papers.

. thereof.

While we have illustrated our invention in connection with a 55 by 50 fabric (meaning 55 warp wires and 50 weft wires to the inch), we can if desired, vary the arrangement, but in each case, v

the tops of the weft knuckles are disposed in substantially the same plane as the top of the belt. For example, on a forty by sixty fabric, we may use a .0125 inch warp wire and-a .009 inch weft wire. Other arrangements utilizing a fifty by forty-five fabric, and a forty-five by fifty, or a fty by fty can also be used, but in each case, the size of wires should be chosen to make the tops of the weft knuckles lie in substantially the same plane as the tops of the warp knuckles..

It is thus apparent that we have solved the problem of two-sidedness in a paper web by so selecting the sizes of warp and weft wires with. reference to the space between them that the tops of the weft wires lie substantially in the same plane as the tops of the warp wires during the weaving operation. With the sizes and spacing heretofore used the plane of the tops of the weft wires are below a plane that passes through the center of the warp knuckles. The fabric which we have obtained is defined as having the plane of the tops of the warp wires substantially in a plane with the tops of the weft wires. To provide a limitation however, for a slight variation between the planes, we have found that satisfactory results can be obtained if the downward limit of the plane passing through the tops of the weft wires is above a plane passing through the centers of the warp wires at the knuckles In Fig. 2, for example, such downward limit is illustrated by the broken line 15.

We claimt- 1. A Fourdrinier paper making wire fabric having warp wires and weft wires wherein the warp wires and weft wires have such relation to each other in size that the plane of the tops of the weft knuckles is disposed above the plane of the center of the warp knuckles and below the plane-of the tops of the warp knuckles whereby a sheet formed thereon possesses substantially the same degree of smoothness on each side thereof.

2. A Fourdrinier paper making wire fabric having warp wires and weft wires woven into a twill weave, wherein the warp Wires have long knuckles and short knuckles, and having the warp wires so selected in size with reference to the weft wires that the tops of the warp knuckles and the tops of the weft knuckles lie substantially in a common plane, whereby a sheet formed thereon possesses substantially the same degree of smoothness on each side thereof.

3. A Fourdrinier making wire fabric, having warp wires and weft wires, the knuckles of which are so positioned with reference to each other during the weaving operation as a result of the selection of size and spacing between the warp and weft wires that a sheet formed thereon possesses the same degree of smoothness on each side thereof.

4. A Fourdrinier paper making wire fabric having warp wires and weft wires, the sizes of which are so chosen and which are so spaced with reference to each other during the weaving operation that the tops of the weft wires lie substantially in the same plane as the tops of the warp wires, whereby a sheet formed thereon possesses substantially the same degree of smoothness on each side thereof.

5. A Fourdrinier paper making wire fabric having warp wires and weft wires woven into a twill weave and having the sizes of the warp wires so selected and spaced with reference to the sizes of the weft wires-` that the tops of the warp knuckles and the tops of the weft knuckles lie substantially in a common plane as a. result of the weaving operation whereby a sheet formed thereon possesses substantially the same degree of smoothness on each side thereof.

6. A Fourdrinier paper making wire fabric having warp wires and weft wires and having warp wires of a different cross sectional size from the weft wires but so related to each other that the tops of the warp knuckles will lie substantially in a common plane during the weaving operation, whereby a sheet formed thereon possesses substantially the same degree of smoothness on each side thereof.

HAMILTON LINDSAY. EDWARD J. BUELL. 

